Bridge–tunnel - online puzzles

A bridge – tunnel is a persistent, unbroken road or rail connection across water that uses a combination of bridges and tunnels, and sometimes causeways, and does not involve intermittent connections such as drawbridges or ferries.

Bridge –tunnels are a common form of fixed link or fixed crossing which replaces ferry service. Fixed links are often, but not necessarily, intercontinental links between continents or transoceanic links to offshore islands.